日 夜(にちや)

にちや

adverb

day and night, constantly

formalliterarydescriptive

1. day and night, constantly, always

Continuously without rest; working or occurring both day and night.

研究者(けんきゅうしゃ)たちは日夜(にちや)努力(どりょく)している。

The researchers are working hard day and night.

日夜(にちや)訓練(くんれん)を続(つづ)けている。

They continue training day and night.

工場(こうじょう)は日夜(にちや)稼働(かどう)している。

The factory operates around the clock.

日夜(にちや) emphasizes tireless, continuous effort — working or happening both day and night without pause.

Compound: 日(にち) (day) + 夜(や) (night)

Register

Somewhat formal and literary. In casual speech, いつも or ずっと would be more natural.

Common patterns

日夜(にちや)努力(どりょく)する: to make efforts day and night
日夜(にちや)研究(けんきゅう)する: to research day and night
日夜(にちや)稼働(かどう)する: to operate around the clock

Similar words

昼夜(ちゅうや): day and night (similar meaning, slightly more neutral)
四六時中(しろくじちゅう): around the clock, constantly (colloquial)
絶(た)えず: constantly, unceasingly (more formal)

Related Words

Synonym: 昼夜(ちゅうや) (day and night)

Compare: 四六時中(しろくじちゅう) (around the clock, constantly)

Compare: 絶(た)えず (constantly, unceasingly)

Compare: 明(あ)け暮(く)れ (day and night)

general

Added 2026.1.11 21:36 · Revised 2026.9.4 21:29

03000/03130_nichiya